Update travis script to psuh to coveralls.io
- .travis.sh: Run
make check-coverage
when running with CC=gcc - .travis.yml: Use the newer trusty tahir builds for updated packages
- .travis.yml: Refactor. Split out the OSX installation steps into .travis_setup.sh . .travis_setup.sh: Same
- Makefile.am: Add --ignore-errors source to lcov command line